Justin Bieber shares plenty of photos via his Instagram and Twitter accounts, letting his horde of female fans in on a bit of his personal life. But the images he uploaded the day before his 18th birthday hammer home the point that The Biebs is growing up, taking the step up into manhood.

He turns 18 tomorrow (March 1) and this photo shows the 'Baby' singer tugging at his famous locks. Instead of being swept to the side, the Bieber bangs are spiky, and he's pulling at a tuft. He's also wide-eyed with wonder. Doesn't he look super serious, in addition to totally adorable?

The Biebs appears pensive, which gives this shot an air of artsy. There's exposed brick behind him, too.

Overall, this is quite possibly one of the hottest and most adult photos The Biebs has ever posted.